PASS
<title>Test that we don't crash when we clone inside DOMContentLoaded</title>
<body>
<style>
* { cursor: -webkit-image-set(url("https://does-not-exist") 251x), pointer; }
</style>
<script>
if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
}

function appendAndClone() {
    document.body.appendChild(document.createElementNS("http://www.w3.org/1998/Math/MathML", "mstack"));
    document.body.cloneNode(true);
    if (window.testRunner)
        testRunner.notifyDone();
}
document.addEventListener("DOMContentLoaded", appendAndClone, false);
</script>
